Michael Clarke wants his team to back up its Ashes whitewash with victory in South Africa

ABC News

Michael Clarke wants Australia's injury uncertainty sorted quickly so the team can prepare as well as possible to take on world Test number one South Africa.

The captain spoke at Sydney airport on Wednesday morning before flying to South Africa and the three-Test tour with the majority of his squad.

Shaun Marsh (calf) and Jackson Bird (back) have been kept behind to prove their fitness, and Clarke would like to have the pair available for Australia's only warm-up match starting on February 5 in Potchefstroom.

That means they will most likely need to be on a flight by the weekend.

Bird bowled well in the nets on Tuesday and will be passed fit if he backs that up with another positive session on Wednesday.

Marsh's calf muscle strain is said to be minor but, given his chequered injury history, medical staff want to see how he responds to treatment in Perth before a final decision is made.